1. Field of the Invention
The present invention relates generally to power distribution equipment and, more particularly, to network protectors. Specifically, the invention relates to a conductive heat sink for use in a network protector.
2. Description of the Related Art
Network power delivery systems are well known in the relevant art for supplying electrical power throughout municipalities and for other applications. Network systems typically include a network bus to which all of the loads are connected, with the network bus typically being of a multi-pole configuration. The network bus is supplied with electricity from a plurality of substations or other power sources that are connected to the network bus. As is further understood in the relevant art, a network protector is electrically interposed between the network bus and each of the power sources in order to insulate the network bus from non-network electrical problems, and for other purposes.
A typical network protector includes a switching apparatus and a fuse that are sealed within a substantially watertight case, and the case is typically disposed below grade for connection with the network bus. A network transformer typically is mounted on the outer surface of the case for stepping down the voltage from the power source level to the network level.
The switching apparatus typically includes a switch that is generally in the configuration of a multi-pole circuit breaker having an operating mechanism and a trip unit, in which the trip unit does not function in response to overcurrent or under-voltage conditions. Rather, the trip unit functions to cause the operating mechanism to separate a set of movable contacts from a set of stationary contacts to interrupt the flow of current therethrough in response to a reverse current situation. The switch also permits manual disconnection of a power source from the network bus for various reasons.
The fuse of the network protector includes a fusible body manufactured out of copper/lead combinations or other materials that xe2x80x9cfusexe2x80x9d or melt under certain specified conditions to protect the network bus. For instance, the fusible body may melt and interrupt current in the event that the network transformer experiences a fault on the secondary winding thereof. Also, the fusible body may melt in the event of a reverse-current condition. The fusible body can also melt in the event of arc faults within the network protector or network transformer, and can also melt in the event of failure of the watertight case whereby water may be admitted into the interior of the case. The fusible body also may melt in the event of a failure with the switch. While such network protectors have been generally effective at achieving their intended purposes, such network protectors nevertheless have not been without limitation.
During operation of the network protector, both the fuse and the switch generate substantial amounts of heat. Such heat, if permitted to be conducted to the network bus, can raise the temperature of the network bus beyond applicable limits. Both the switch and the fuse are, however, sealed within the case which is watertight, whereby convection of the heat directly away from the fuse and the switch is extremely limited. It is thus desired to provide a network protector having an enhanced ability to cool the fuse and the switch thereof within the confines of the watertight case.
In view of the foregoing, a conductive heat sink is electrically interposed between a fuse and a switching apparatus within a watertight case of a network protector. The heat sink is advantageously configured to conduct current between the switching apparatus and the fuse. During operation, the skin effect causes the electricity conducted by the heat sink to flow primarily through the outer regions of the heat sink, thereby resulting in the generation of heat at the outer regions of the heat sink due to electrical resistance. The heat sink includes a core from which a plurality of fins extend. The fins conduct and convect heat away from the outer regions of the heat sink, which reduces the temperature thereof and correspondingly increases the conductivity of the outer regions of the heat sink.
As such, an object of the present invention is to provide a conductive heat sink that can be used in a network application.
Another object of the present invention is to provide a conductive heat sink that conducts power therethrough.
Another object of the present invention is to provide a conductive heat sink that convects heat to its surrounding environment.
Another object of the present invention is to provide a conductive heat sink that can conduct heat away from componentry with which the heat sink is connected.
Accordingly, an aspect of the present invention is to provide an electrically conductive heat sink structured to be electrically interposed within an electrical circuit between a first conductor having a first electrical potential and a second conductor having a second electrical potential, the first electrical potential being different than the second electrical potential, in which the general nature of the heat sink can be stated to include a core, a plurality of fins extending outwardly from the core, the core and the fins being integrally formed with one another as a monolithic member, and the core having an initial end and a terminal end opposite one another. The initial end is structured to be electrically conductively engaged with the first conductor of the electrical circuit, the terminal end is structured to be electrically conductively engaged with the second conductor of the electrical circuit. The heat sink is manufactured at least partially out of an electrically conductive material and is structured to conduct current between the first conductor and the second conductor. The initial end and the terminal end each include one of a socket and a fastener.
In an embodiment of the heat sink, the initial end includes a socket that extends into a substantially planar first engagement surface and that is threaded and is structured to received a first threaded fastener therein, and the terminal end includes a second threaded fastener that extends outwardly from a substantially planar second engagement surface. In another embodiment the heat sink is formed by casting the electrically conductive material around the second threaded fastener.
Another aspect of the present invention is to provide in combination a fuse and an electrically conductive heat sink. The heat sink is electrically and thermally conductively engaged with the fuse, with the heat sink being structured to be electrically conductively connected with a conductor and being structured to conduct current between the conductor and the fuse and being further structured to conduct heat away from the fuse. The heat sink can be generally stated as including a core and a plurality of fins extending outwardly from the core, with the core and the fins being integrally formed with one another as a monolithic member, and with the core having an initial end and a terminal end opposite one another. The initial end is structured to be electrically conductively engaged with the conductor, and the terminal end is structured to be electrically and thermally conductively engaged with the fuse. The heat sink is manufactured at least partially out of an electrically conductive material. The initial end includes one of a socket and a fastener, and the terminal end includes one of a fastener protruding outwardly therefrom and a socket having a fastener therein.
Still another aspect of the present invention is to provide a network protector that can be generally stated as including a switching apparatus, a fuse, and an electrically conductive heat sink electrically interposed between the switching apparatus and the fuse. The heat sink is structured to conduct current between the switching apparatus and the fuse, and is further structured to conduct heat away from the fuse. The heat sink includes a core and a plurality of fins extending outwardly from the core, with the core and the fins being integrally formed with one another as a monolithic member. The core has an initial end and a terminal end, with the initial end being electrically conductively engaged with the switching apparatus, and the terminal end being electrically and thermally conductively engaged with the fuse. The heat sink is manufactured at least partially out of an electrically conductive material.